Routine childhood immunization in Sub-Saharan Africa: addressing parental vaccine hesitancy

OBJECTIVES

Parental vaccine hesitancy (VH) is a major barrier to childhood vaccination. We aimed to identify the determinants of parental VH towards routine childhood immunization in 12 Sub-Saharan African countries.

STUDY DESIGN

A cross-sectional study was conducted from November 1 to December 15, 2022.

METHODS

Parents of children aged 19 months to 6 years and residing in the Sub-Saharan Africa were included. An anonymous online survey and face-to-face interviews were conducted. The Parent Attitude about Childhood Vaccine Scale was used to identify vaccine-hesitant parents. Multivariate regression and mediating analysis were performed.

RESULTS

Across the 5032 participants, 21.2% were hesitant towards routine childhood immunization. Urban residents (adjusted odds ratio [AOR] = 1.32, 95% confidence interval [CI]: 1.10-1.58), non-first-born children (AOR = 1.54, 95% CI: 1.19-1.98), and chronically ill children (AOR = 2.00, 95% CI: 1.69-2.37) increased the likelihood of parental VH. Mothers with higher education, attending at least one antenatal care (ANC) visit (AOR = 0.25, 95% CI: 0.19-0.32), and had a healthcare facility-based delivery (AOR = 0.55, 95% CI: 0.44-0.70) decreased the odds of parental VH. Parental VH mediated the effect of ANC and mothers' age on vaccination uptake. ANC increased the odds of vaccination uptake (odds ratio [OR] = 12.49, 95% CI: 9.68-16.13). Parental VH mediated the association between ANC and vaccination uptake, decreasing the likelihood of vaccination uptake (OR = 0.12, 95% CI: 0.10-0.14). Each additional year of the mother's age decreased the odds of vaccination uptake (OR = 0.95, 95% CI: 0.95-0.96). The indirect effect of mother's age on vaccination through parental VH decreased the odds of vaccination uptake (OR = 0.45, 95% CI: 0.44-0.45). Parental VH continued to be a mediator of the combined effect of mother's age and ANC on vaccination uptake, decreasing the likelihood of vaccination uptake (OR = 0.0017, 95% CI: 0.00166-0.00168).

CONCLUSIONS

Context-specific interventions are needed to address parental VH and improve vaccine acceptance and coverage.

Mucosal exposure to non-tuberculous mycobacteria elicits B cell-mediated immunity against pulmonary tuberculosis

Bacille Calmette-Guerin (BCG) is the only licensed vaccine against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB) disease. However, BCG has limited efficacy, necessitating the development of better vaccines. Non-tuberculous mycobacteria (NTMs) are opportunistic pathogens present ubiquitously in the environment. TB endemic countries experience higher exposure to NTMs, but previous studies have not elucidated the relationship between NTM exposure and BCG efficacy against TB. Therefore, we develop a mouse model (BCG + NTM) to simulate human BCG immunization regime and continuous NTM exposure. BCG + NTM mice exhibit superior and prolonged protection against pulmonary TB, with increased B cell influx and anti-Mtb antibodies in serum and airways, compared with BCG alone. Notably, spatial transcriptomics and immunohistochemistry reveal that BCG + NTM mice formed B cell aggregates with features of germinal center development, which correlate with reduced Mtb burden. Our studies suggest a direct relationship between NTM exposure and TB protection, with B cells playing a crucial role.

Mycobacterium avium via oral route provide enhanced protection against pulmonary tuberculosis: An essential role of B cells and germinal centers

Human tuberculosis (TB) is caused mainly by Mycobacterium tuberculosis (Mtb) and represents an enormous challenge to global health because of the inadequacy of currently available drugs and vaccines. The most common clinical manifestation is pulmonary TB, and the Bacille Calmette Guerin (BCG) is the only licensed vaccine for protection against TB; however, its efficacy is highly variable. Today at least 52 countries have reported MDR-TB and XDR-TB cases which cannot be cured or contained by current TB therapy. Thus, there is an urgent need to develop new therapies/vaccines that effectively prevent or cure TB. In the last decade, lymphoid follicles (LFs) having ectopic GCs (eGC) have been identified in the lungs of Mtb infected animals and humans; however, a mechanism of its formation and role has not been adequately characterized. Our studies found that mice vaccinated with BCG and exposed to Mycobacterium avium [a non-tuberculous mycobacterium (NTM)] via drinking water provide long-term protection from pulmonary TB than BCG alone as determined by reduced Mtb bacterial burden and inflammatory progression of infection. Interestingly, these mice also developed eGC in the lungs and have increased B cells, anti-Mtb cell lysate specific IgA, and IgG antibodies. These findings suggest that NTM and B cells play a critical role in generating protective immunity against pulmonary Mtb infection, and the formation of eGC in these mice is a crucial factor in this improved immunity. Investigating the mechanism of eGC formation and the role of NTM and B cells in its stimulation is an important question to understand TB pathogenesis and to develop effective vaccines and therapies.

Supported by NIH/NIAID - 1R01AI127475-01AI, Colorado State University's MIP research team grant

Effect of non-tuberculous mycobacteria on the protective efficacy of BCG vaccine via modulation of mucosal immunity

Tuberculosis (TB) continues to increase worldwide despite vigorous attempts to control it. Bacillus Calmette-Guerin (BCG) is the only licensed vaccine currently available for protection against TB, however, its efficacy is highly variable between countries. It has been hypothesized that BCG’s variable protection is due, amongst others, to immunological interference by environmental, non-tuberculous mycobacteria (NTM). However, a definitive mechanism has not been identified so far. Considering the foregoing, we developed a murine model closely resembling the natural history of human exposure to different mycobacterial species, including: 1) BCG vaccination at an early age; 2) exposure to viable NTMs (Mycobacterium avium subsp. avium) via the oral route and 3) maintaining continuous NTM exposure even after TB infection, as occurs in endemic places. Surprisingly, we found that a low dose of NTM via the oral route enhanced BCG-mediated protection 30 days post infection, as determined by decreased TB burden in lungs and spleens of infected mice. We hypothesized that upon oral intake, NTMs would interact with intestinal Peyer’s Patches (PPs) and activate mucosal immune responses. Therefore, we evaluated immune cell populations present in PPs and lungs using flow cytometry. Fifteen days after initiating NTM feeding, higher influx of B220hiMHC-IIhi B cells was observed in PPs of NTM exposed mice, regardless of BCG vaccination status. Similarly, NTM exposure augmented pulmonary CD62LintMHC-IIhiCD19hiB and CD4+ T cells. These results suggest that NTM exposure via the oral route elicit humoral mucosal immunity against TB, and this will be further dissected to leverage mucosal NTMs as a strategy to boost BCG.

Efficacy of Nootka Oil as a Biopesticide for Management of Imported Fire Ants (Hymenoptera: Formicidae)

Recent concerns regarding the impact of traditional synthetic pesticides on nontarget organisms have generated demand for alternative products with lower environmental impact. This demand has led to increasing focus on plant essential oils as sources of new biopesticides. In this study, we demonstrate that the essential oil of the Alaskan yellow cedar, Cupressus nootkatensis (D. Don) Spach, has activity against hybrid imported fire ant workers, Solenopsis invicta Buren × Solenopsis richteri Forel. In digging assays, ants were repelled by nootka oil and digging continued to be suppressed by nearly 50% in nootka oil-treated sand aged 6 mo in the laboratory. Higher worker mortality was also observed in contact and fumigation assays compared to control checks. In a field drench test, mortality of mounds treated with nootka oil lagged behind mounds treated with bifenthrin treatment for 7 wk, but both nootka oil and bifenthrin had higher mortality than the untreated check at the end of the 12-wk evaluation period. In a band application evaluation, nootka oil plots maintained a 90-95% reduction in fire ant mounds from the 2nd to 17th wk, when new mounds began to intrude on the field plots. The quarantine-approved bifenthrin band treatment maintained 100% control from the 2nd to 24th wk. Although the formulation tested here did not perform to Federal Imported Fire Ant Quarantine standards, other formulations may enable this product to reach 100% control. In addition, nootka oil could be beneficial in situations where ant suppression rather than complete quarantine elimination is the management goal.

Serum concentration of IL-17, IL-23 and TNF-α among patients with chronic spontaneous urticaria: association with disease activity and autologous serum skin test

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common skin disorder, which is considered in a subset of patients to be an autoimmune disorder. T helper 17 (Th17) cells are crucially involved in the pathogenesis of some autoimmune diseases.

OBJECTIVES

Our aim was to test the association of Th17 with CSU. We examined interleukin (IL)-17, IL-23 and tumor necrosis factor-alpha (TNF-α) serum levels in CSU patients and studied their association with urticaria activity and autologous serum skin test (ASST).

SUBJECTS AND METHODS

Serum concentration of IL-17, IL-23 and TNF-α were measured in 75 patients with CSU and 30 healthy control subjects. Disease activity was assessed by using urticaria activity score (UAS) as recommended by EAACI/GA(2)LEN/EDF/WAO Guidelines.

RESULTS

Serum concentration of IL-17, IL-23 and TNF-α were significantly higher in CSU patients as compared with the healthy control subjects (mean: 35.51 ± 31.14 vs. 4.60 ± 1.38 pg/mL; P < 0.001, 38.95 ± 27.82 vs. 9.87 ± 4.62 pg/mL; P > 0.001 and 17.93 ± 6.05 vs. 6.87 ± 3.73 pg/mL; P = 0.004, respectively). There were significant positive correlation between serum IL-17, IL-23, TNF-α and disease activity assessed by cumulative UAS for 7 days before blood sampling. The Serum concentration of IL-17, IL-23 and TNF-α were also significantly higher in ASST positive patients than in ASST negative patients.

CONCLUSION

Our results showed high serum levels of IL-17, IL-23 and TNF-α among CSU patients which may highlight a functional role of these cytokines in the pathogenesis of this important and common skin disease. It also may provide the rationale for new treatment strategies in chronic urticaria.

Evaluation of a Single Application of Neonicotinoid and Multi-Application Contact Insecticides for Flatheaded Borer Management in Field Grown Red Maple Cultivars

Two trials evaluated insecticides for flatheaded borer control and effect on red maple (Acer rubrum L.) cultivar growth over 4 years. Chrysobothris femorata (Olivier) was the only species reared from borer damaged maples during the study. Soil-applied systemic insecticides (acephate, imidacloprid, clothianidin, dinotefuran, and thiamethoxam) and trunk-applied contact insecticides (chlorpyrifos and bifenthrin) were tested. In the 2005 trial, a one-time drench of Allectus (imidacloprid + bifenthrin) or Discus (imidacloprid + cyfluthrin) provided 2 to 4 years of protection with ‘Autumn Flame’ and ‘Franksred’ from C. femorata. Soil-applied experimental imidacloprid tablets prevented borer damage in the third and fourth post-treatment years, but were not as effective as imidacloprid drenches in the first two years. Soil applied acephate tablets, chlorpyrifos (Dursban 4E) trunk sprays, or untreated control plants had borer damage each year, which totaled up to 41.7% damage by year 4 in ‘Autumn Flame’. Trunk diameter growth and tree canopy size was greater with Discus drench or imidacloprid tablet treatments than other treatments. In the 2006 trial, drenches of Allectus, Discus, or Safari 20SG (dinotefuran) applied in May and Discus or Arena 50WDG (clothianidin) drenches applied in March provided complete protection from C. femorata the first year in ‘Fairview Flame’, ‘Franksred’, and ‘October Glory’. Discus (March) drench provided four years of complete protection among the three cultivars, while other neonicotinoid drenches had 3.7–6.3% (Arena March), 3.7–12.5% (Arena May), 0–6.3% (Discus May), 0–10.3% (Safari), and 12.5–20.5% (Flagship) total damage. Ineffective treatments included an experimental imidacloprid gel (7.4–18.8% damage), acephate tablets (18.5–75.0%), Onyx Pro Insecticide (5.1–18.8%), Dursban 2E (11.1–31.3%), one imidacloprid tablet (15.4–43.8%), or untreated plants (32.1–41.0%). This study demonstrates a single application of some neonicotinoid treatments can provide multi-year C. femorata prevention, increased maple trunk growth, and provide borer protection superior to trunk sprays.

In situ biosurfactant production by Bacillus strains injected into a limestone petroleum reservoir

Biosurfactant-mediated oil recovery may be an economic approach for recovery of significant amounts of oil entrapped in reservoirs, but evidence that biosurfactants can be produced in situ at concentrations needed to mobilize oil is lacking. We tested whether two Bacillus strains that produce lipopeptide biosurfactants can metabolize and produce their biosurfactants in an oil reservoir. Five wells that produce from the same Viola limestone formation were used. Two wells received an inoculum (a mixture of Bacillus strain RS-1 and Bacillus subtilis subsp. spizizenii NRRL B-23049) and nutrients (glucose, sodium nitrate, and trace metals), two wells received just nutrients, and one well received only formation water. Results showed in situ metabolism and biosurfactant production. The average concentration of lipopeptide biosurfactant in the produced fluids of the inoculated wells was about 90 mg/liter. This concentration is approximately nine times the minimum concentration required to mobilize entrapped oil from sandstone cores. Carbon dioxide, acetate, lactate, ethanol, and 2,3-butanediol were detected in the produced fluids of the inoculated wells. Only CO(2) and ethanol were detected in the produced fluids of the nutrient-only-treated wells. Microbiological and molecular data showed that the microorganisms injected into the formation were retrieved in the produced fluids of the inoculated wells. We provide essential data for modeling microbial oil recovery processes in situ, including growth rates (0.06 +/- 0.01 h(-1)), carbon balances (107% +/- 34%), biosurfactant production rates (0.02 +/- 0.001 h(-1)), and biosurfactant yields (0.015 +/- 0.001 mol biosurfactant/mol glucose). The data demonstrate the technical feasibility of microbial processes for oil recovery.

Breast inflammatory gigantomastia in a context of immune-mediated diseases

CONTEXT

Localized breast lesions have been described in lupic or diabetic patients. However, the description of breast gigantomastia in women presenting with autoimmune diseases has not been reported.

SETTING

The study took place within the Department of Endocrinology and Reproductive Medicine, Necker Hospital, Paris, France.

PATIENTS

We describe eight patients with inflammatory gigantomastia, occurring in a context of immune-mediated diseases: myasthenia, chronic arthritis, or thyroiditis.

MAIN OUTCOME MEASURES

Together with hormonal, immunological, and breast magnetic resonance imaging (MRI) evaluation, breast histology enabled us to perform immunocytochemical and indirect immunofluorescence studies. Control sera were obtained from patients with (n = 10) and without (n = 7) antinuclear antibodies.

RESULTS

Six of the eight patients developed gigantomastia either at puberty or during pregnancy. Neither a hormonal oversecretion nor a specific immunological pattern was observed. All patients except one presented antinuclear antibodies. Histological study revealed a diffuse, stromal hyperplasia and a severe atrophy of the lobules. A rarefaction of adipocytes was also noted, as previously suggested on MRI. There was a perilobular lymphocytic infiltrate made of CD3+ lymphocytes. Study of sera from five of six cases of gigantomastia showed a nuclear immunofluorescence pattern in normal mammary ductal and lobular glandular epithelium, as well as in kidney and intestine epithelial cells. In control sera, a nuclear signal was observed only when antinuclear antibodies were present.

CONCLUSIONS

We suggest that breast tissue may be a target tissue in autoimmune diseases, this process being favored by the hormonal milieu. However, the precise mechanism of such association is not individualized. The fact that stromal hyperplasia is the main histological feature justifies the search for the involvement of growth factors in such a process.

Non-alcoholic duct destructive chronic pancreatitis: a histological, immunohistochemical and in-situ apoptosis study of 18 cases

AIMS

To assess retrospectively pancreatic changes in non-alcoholic duct-destructive chronic pancreatitis and to investigate the role of apoptosis in duct destruction.

METHODS AND RESULTS

Eighteen patients (mean age 46 years, nine women and nine men) underwent pancreatic resection for suspected pancreatic tumour and were diagnosed as having non-alcoholic duct-destructive chronic pancreatitis. We performed a morphological study either semiquantitatively (fibrosis and inflammation) or quantitatively (CD3+ intraepithelial lymphocytes, M30 and TUNEL+ apoptotic cells). The results were compared with those obtained in 10 cases of chronic alcoholic pancreatitis and nine cases of chronic obstructive pancreatitis. Pancreatic changes were diffuse and heterogeneous in 14 cases, but segmental in four cases. The main pancreatic lesions were ductal epithelial alteration, periductal inflammation and fibrosis. There were no cysts or calcifications. We found a marked increase in mast cells in the infiltrate, a slight increase in TiA1+ lymphocytes and in intraepithelial lymphocytes compared with other types of chronic pancreatitis. No significant increase in ductal apoptosis was observed.

CONCLUSION

Non-alcoholic duct-destructive chronic pancreatitis is a well-defined pathological entity, distinct from alcoholic and obstructive chronic pancreatitis. Our results indicate that apoptosis probably does not play a major role in ductal alterations.

In situ detection of telomerase enzymatic activity in human hepatocellular carcinogenesis

Telomerase enzymatic activity has been detected in most human malignant tumours including hepatocellular carcinoma. In order to assess the cellular source, the topographic distribution, and the chronology of telomerase re-expression during human liver carcinogenesis, an in situ technique derived from the standard TRAP (telomeric repeat amplification protocol) assay was set up that allowed the detection of telomerase enzyme activity at the cellular level on frozen liver tissue sections. In situ TRAP (ISTRAP) was performed on 27 hepatocellular carcinomas (HCCs) and 57 non-tumour livers, including normal liver without HCC, liver samples adjacent to tumour with and without hepatic cirrhosis, and biopsies of chronic hepatitis. In HCC, telomerase was detected in the nuclei of liver tumour cells in 23/27 cases (85%), with a heterogeneous distribution within the tumour. This signal was also detected in clusters of hepatocytes in 16/26 (61%) samples of liver adjacent to HCC, in 10/23 (43%) cases of chronic viral hepatitis without adjacent HCC, and in scattered nuclei of 2/8 histologically normal livers. Comparison of the results obtained with ISTRAP and standard TRAP assays on tissue extracts suggests a gain in sensitivity with the in situ technique. This study confirms that telomerase is expressed in most HCCs and suggests that focal telomerase reactivation is an early event during human liver carcinogenesis. ISTRAP is a sensitive technique that allows the study of telomerase expression in the morphological context.

Replicative senescence in normal liver, chronic hepatitis C, and hepatocellular carcinomas

There is growing evidence that senescent cells accumulate in vivo and are associated with the aging process in parallel with the progressive erosion of telomeres. Because recent data show that telomere shortening is involved in the pathogenesis of liver cirrhosis, we looked for replicative senescence cells in normal livers, chronic hepatitis C, and hepatocellular carcinoma (HCC). Replicative senescent cells were detected on liver tissue cryosections using expression of a specific marker, senescence-associated beta-galactosidase, a cytoplasmic enzyme detected at pH 6. A total of 57 frozen liver samples (15 normal liver, 32 chronic hepatitis C, and 10 HCCs) were studied. Replicative senescence was graded as absent in 56% of cases (32 of 57) and present in 44% (25 of 57). Replicative senescence was considered present in 3 of 15 normal livers (20%), 16 of 32 chronic hepatitis cases (50%), and 6 of 10 HCCs (60%). In the group of nontumoral livers, the presence of senescent cells in liver was associated with older age (P =.03). In the group with chronic hepatitis C, fibrosis stage, but not activity grade, was significantly correlated with the accumulation of replicative senescent cells (P <.001). Finally, beta-Gal staining in nontumoral tissue was strongly correlated with the presence of HCC in the surrounding liver (P <.001). These results suggest that chronic hepatitis C represents a relevant model of accelerated replicative senescence and that accumulation of replicative senescent cells predispose to HCC development. Detection of replicative senescent cells may then serve as a predictive marker of a hepatocellular carcinoma in the surrounding tissue. HUM PATHOL 32:327-332.

Two unusual tumors in a patient with xeroderma pigmentosum: atypical fibroxanthoma and basosquamous carcinoma

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease, characterized by a genetic defect in DNA repair. The consequence is a high incidence of skin cancers on sun-exposed cutaneous surfaces of affected children. First lesions appear in the first years of life: telangiectasia, actinic keratosis and keratoacanthomas. Squamous cell and basal cell carcinomas are the most frequent neoplasms. We report the case of a 6-year-old girl affected with XP, who developed two unusual tumors: an atypical fibroxanthoma and a basosquamous carcinoma. In both tumors, immunohistochemical study showed abnormal accumulation of the p53 protein, suggesting the presence of mutation of the p53 tumor suppressor gene. Such p53 mutations may be ultraviolet (UV)-induced, as they are frequently observed in tumors occurring in XP.

Ethylmalonic aciduria: an organic acidemia with CNS involvement and vasculopathy

Five infants from 3 families, one Egyptian, two Yemeni, are described with a progressive encephalopathy, four of whom have been studied in detail. All patients showed vascular lesions of the skin, characterized by waxing and waning petechiae and ecchymoses. Acrocyanosis was present in three patients. All patients showed retinal lesions characterized by tortuous veins. Protracted diarrhea was not a consistent finding, although they had metabolic crisis in association with diarrhea. They did not show failure to thrive. The neurologic symptoms were indicative of a progressive pyramidal tract disease. Three patients died following sudden emergence of severe basal ganglia, putaminal and head of caudate lesions. In one patient the CT changes in brain were suggestive of infarction. The patients who died manifested pulmonary congestion, or wet lung, and respiratory difficulties during the terminal stage of the disease. In all patients before and during the terminal event, mild-to-moderate hematuria, and in two RBC in CSF, was observed. In one patient there was mild hemoperitoneum at the terminal event. The urine organic acids indicated increased excretion of ethylmalonic, methylsuccinic, glutaric, and adipic acids. The patients invariably showed lactic acidosis, but no ketosis, during and in between the acidotic attacks of the disease. The acylcarnitine profile in blood of two patients showed a pronounced increase in C4 and C5 carnitine esters. In three patients, biopsies from petechiae indicated absence of an immune event, showing only fresh hemorrhage. An immunologic study in one patient was normal for the suppressor:cytotoxic lymphocyte ratio and concentration of interleukin-2 receptor during and in between hemorrhagic attacks. The cytochrome c oxidase activity in fibroblasts was normal. The rate of oxidation of glucose, leucine, isoleucine, valine, propionate and butyrate by fibroblasts was normal. The disease is not responsive to treatment with riboflavin, ascorbic acid, vitamin E, glycine, or carnitine. One patient remained stable on prolonged large doses of methylprednisolone. The biochemical defect leading to ethylmalonic aciduria in this disease remains unknown.

Biochemical heterogeneity of infantile central nervous system spongy degeneration

Aspartoacylase, the enzyme whose activity is deficient in infantile central nervous system spongy degeneration (Canavan-Van Bogaert-Bertrand disease), is detected as an approximately 59-kD protein in the Sephadex G-200 filtration of normal fibroblast extracts. The enzyme activity in homogenates of fibroblasts is protected by leupeptin, a protease inhibitor. In the absence of leupeptin, 90% of aspartoacylase activity is lost. In some patients with infantile spongy degeneration, no activity (less than 2%) can be detected. In some other patients with residual activity in fibroblasts, two separate peaks of enzyme are eluted with molecular weight corresponding to approximately 59 and 19 kD. Aspartoacylase activity in this latter group is protected to the same extent by the presence of leupeptin. However, the elution of two peaks is independent of the presence of leupeptin. This study indicates biochemical heterogeneity in the pathogenesis of infantile spongy degeneration.

[Evolution of the parietal incision in cesarean sections]

This concerns a multicenter study including 51 centers of the North, Picardy and Champagne areas, 35 public institutions and 16 private institutions. This study was carried out on 7,216 records of Caesarean sections, collected between 1978 and 1983. The objective of this study was to specify maternal and fetal morbidity in Caesarean sections. In this study, the authors attempted to establish a correlation between this morbidity and the parietal incision, as well as compare the responsibility of each of the two incisions that were performed: midline infraumbilical and Pfannenstiel's incision. From a neonatal standpoint, they have demonstrated that the type of parietal incision has no bearing on the condition of the child at birth, in spite of a slightly longer extraction time in the Pfannenstiel incision. From a maternal standpoint, they found a similar number of wall abscesses and wound dehiscence. Abdominal wall hematomas are slightly more frequent with the Pfannenstiel incision and this difference is significant. The reservations formulated concerning transverse incisions and especially the Pfannenstiel incision do not appear to be justified.

An epidemiologic study of the fungal skin flora among the elderly in Alexandria

The fungal skin flora of a sample of 205 elderly persons in Alexandria, drawn by cluster sampling probability technique, was investigated. Pathogenic yeasts were isolated from 18.6% and 10.3% of skin and nails respectively. Candida albicans (16.1% and 7.3%) was prominent. A low prevalence of dermatophytes grown on agar (2.4% from skin and 2.9% from nails) was observed. In contrast, saprophytic filamentous fungi comprised 45.4 and 50.7% of skin and nails samples respectively. This study showed no statistically significant effect of sociodemographic variables (sex, marital status, crowding index, and income per capita) on the skin flora. There was no statistical significant difference between elderly diabetics and non-diabetics as regards fungal skin flora.

Ecological effects of antibiotic production by dermatophyte fungi

Antibiotic production by dermatophyte fungi has been demonstrated in vivo in the lesions of patients with dermatomycoses. Patients infected with antibiotic-producing strains more frequently carried cocci resistant to penicillin and other antibiotics than did patients infected with non-producer strains. The total bacterial load was less in lesions caused by producer fungi. In vitro studies demonstrated the selection of penicillin-resistant S. aureus from mixed populations of resistant and sensitive cells.

Antibiotic production by dermatophyte fungi

Thirty-two clinical isolates of anthropophlic dermatophytes were examined for their capacity to produce antibiotics in liquid culture and on human stratum corneum in vitro. Antibiotics were detected and classified using agar diffusion bioassays and chromatographic analysis. Twenty-four isolates produced antibiotic substances in liquid culture filtrates; some strains produced more than one antibiotic. Only four isolates produced detectable levels of antibiotics when grown on stratum corneum unless an artificial sweat mixture was used as a nutrient supplement, when the number rose 11. Respresentatives of all species studied produced benzyl penicillin-like substances. Some Trichophyton isolates also produced streptomycin-like antibiotics, a characteristic previously unrecorded for eukaryotic organisms. Other antibiotics, which apart from azalomycin F could not be properly classified, were produced by Epidermophyton floccosum. Antibiotic production occurred over the normal skin temperature range but sometimes the type of antibiotic produced and the frequency of detection appeared to be influenced by the incubation temperature.

Determination of the dipole moments of some polar liquids dissolved in polar solvents

The application of a modified form of the Onsager equation at the condition of infinite dilution of a polar solute in a polar solvent leads to reasonable dipole moments for water, pyridine, acetone, tert-butyl alcohol, n-butyl alcohol, and β-octyl alcohol, except in the case of water in tert-butyl alcohol at 30 and 40 °C and the case of acetone in n-butyl alcohol at 30 to 50 °C. The initial decrease of the dielectric constant of solvent by addition of solute in each of these two cases is associated with a reduction in the Kirkwood g-factor of solute. In all 12 systems investigated, strong hydrogen bonding occurs between solute and solvent molecules and often between solvent molecules themselves. It is thought that this equation must fail when short-range interactions assume predominant importance, but why it works so well for those cases which are also strongly interacting systems is not clear.